Reigning EU champion and European bronze-medallist Walker was a comfortable winner in his men’s bantamweight opener in Belarus, scoring a 4-1 victory on the judges’ scorecards over Armenia’s Zhirayr Sargsyan in the last-16 at the Uruchie Sports Palace.

The 24-year-old from Lisburn is now through to a quarter-final outing on Wednesday against Samuel Kistohurry of France, who scored a unanimous points win over Raffaele di Serio of Italy.

Walker admitted: “He was very, very good - better than I expected. He was very fit.

“This was his second fight and he was probably more warmed up, I felt a bit rusty in there, but it will stand me well for the quarter-final bout.”

But Gardiner fell on a 4-1 scoreline to tough-punching Mikheil Bakhtidze of Georgia.

Clonmel-based Gardiner was considered by four of the five judges to have taken the opening round.

However, rounds 2 and 3 swung Bakhtidze’s way, as the Georgian’s powerful hits made a serious impact, forcing a cut.

Molloy also fell at welterweight in the last-16 to home Belarussian dangerman Yauheni Dauhaliavets, again on a 4-1 judges’ decision.

Only Bulgarian judge Pavel Pavlov scored the first two rounds Molloy’s way, and the other four sided with the Belarus fighter.

Indeed, he scored every round Molloy’s way, but with two judges viewing it as a 30-27 triumph for Dauhaliavets, and the other two as a 29-28 win for the Belarussian, it was the end of the road for the twice Irish elite champion.

There was better news on the opening day of women’s boxing, as 12-time national champion Michaela Walsh turned over Romania’s Lenuta-Lacramioara Perijoc at featherweight on a 4-1 judges’ scoreline.

Walsh had beaten the Romanian in the semi-finals on the way to winning the recent Cologne Boxing World Cup in Germany.

She awaits Germany’s reigning world champion Ornella Wahner in Wednesday’s quarter-finals.

Welterweight Grainne Walsh saw off Britain’s Rosie Eccles on a similar 4-1 result.

She now fights Finland’s European Champion Elina Gustafsson in the quarters on Wednesday, and commented: “It’s always a tough fight with GB - I’ve fought that girl before and it was another close decision today.

“All the people in my weight are up there at world level so there’s no easy draw.

“I’m just happy to get the first one done. She was very tough, very physical. It was a great scrap - a proper dog fight and I’m delighted with the win.”

Gustafsson will be a tough prospect for Walsh in the last-eight though in what will be the Finn’s first bout, after receiving a first-round bye.